System and method for stereo operation of microphones for video conferencing system

• US 20060221177A1
• Filed: 03/30/2005
• Published: 10/05/2006
• Est. Priority Date: 03/30/2005
• Status: Active Grant

• Current Assignee: Polycom Incorporated (Plantronics, Inc.)
• Original Assignee: Polycom Incorporated (Plantronics, Inc.)
• Inventors: Chu, Peter, Duys, Anthony M.
• Granted Patent: US 7,646,876 B2
• Time in Patent Office: Days
• US Class Current: 348/14.120
• CPC Class Codes: H04N 7/142 Constructional details of the terminal equipment, e.g. arrangements of the camera and the display
• CPC Class Codes: H04R 27/00 Public address systems circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; monitoring or testing arrangements for public address systems H04R29/007; amplifiers H03F

Abstract

A microphone bar for obtaining audio input for a video conferencing system includes a master module and one or more slave modules. The master module houses a first pair of unidirectional microphones for obtaining audio from opposite sides of the bar, and each of the slave modules houses a second pair of unidirectional microphones for obtaining audio from opposite sides of the bar. Extensions connect the modules together, and at least one bus conducts audio signals through the extension from the microphones to the video conferencing system. The microphones are operable according to a broadside mode of stereo operation when a central axis of the bar is substantially orthogonal to a view angle of the conferencing system. Furthermore, the microphones are operable according to an end-fire mode of stereo operation when the central axis of the bar is substantially parallel to the view angle of the conferencing system.

Claims

1. A video conferencing system having a camera with a view angle, comprising:

a plurality of modules, each module having at least one microphone operable to obtain audio, each module being positionable in at least two orientations relative to the view angle of the camera; and

a control unit operatively coupled to the camera and the plurality of microphones, the control unit being operable to control the audio according to at least two modes of stereo operation depending on which of the at least two orientations the microphones are positioned relative to the view angle of the camera.

2. The system of claim 1, wherein the plurality of modules are physically connected together to form a microphone bar.

3. The system of claim 2, wherein the microphone bar comprises at least two modules, each module housing at least two unidirectional microphones substantially oriented towards opposite sides of a central axis defined by the microphone bar.

4. The system of claim 1, wherein each module houses at least one unidirectional microphone, and wherein the plurality of modules are capable of being arranged to substantially define a central axis, whereby:

a first plurality of unidirectional microphones are mounted substantially along a first side of the central axis; and

a second plurality of unidirectional microphones are mounted substantially along a second side of the central axis.

5. The system of claim 4, wherein at least one of the modules comprises three cardioid microphones pointing radially outward from the module at about 120-degrees apart from one another.

6. The system of claim 4, wherein the at least two modes of stereo operation include a broadside mode of stereo operation when the central axis is substantially orthogonal to the view angle of the camera.

7. The system of claim 6, wherein in the broadside mode the plurality of microphones on the side of the central axis closest to the camera are deactivated and the plurality of microphones are divided into left and right sides of stereo audio input.

8. The system of claim 4, wherein the at least two modes of stereo operation include an end-fire mode of stereo operation the central axis is substantially parallel to the view angle of the camera.

9. The system of claim 8, wherein in the end-fire mode the plurality of microphones on one side of the central axis are designated as one side of stereo audio input and the plurality of microphones on the other side of the central axis are designated as another side of stereo audio input.

10. The system of claim 1, wherein the control unit is configured to execute a tone operation automatically detecting an orientation of the microphones.

11. The system of claim 10, wherein in the tone operation, the control unit causes a tone to be emitted, and wherein the control unit compares an attribute of the tone detected by two or more of the plurality of microphones to determine an orientation of the microphones.

12. The system of claim 1, further comprising:

a first electronic compass obtaining a first orientation of the camera, the control unit, or a display; and

a second electronic compass obtaining a second orientation of one or more of the modules,

wherein the control unit compares the first and second orientations to automatically determine a relative orientation of the one or more modules with respect to the camera, the control unit, or the display.

13. The system of claim 1, further comprising:

a detector operatively coupled to the control unit; and

a plurality of emitters mounted on one or more of the modules, each emitter emitting a signal,

wherein the control unit determines the orientation of the microphones in the modules based on the signal detected by the detector.

14. A video conferencing system, comprising:

a plurality of microphones being operable to obtain audio;

means for determining the orientation of the microphones relative to the videoconferencing system; and

means for controlling audio operation of the videoconferencing system according to at least two modes of stereo operation depending on the orientation of the microphones relative to the videoconferencing system.

15. The system of claim 14, wherein the means for controlling the audio includes means for deactivating microphones closest to the video conferencing system and for dividing remaining microphones into left and right sides of stereo audio input.

16. The system of claim 14, further comprising means for manually selecting a mode of stereo operation.

17. The system of claim 14, further comprising means for automatically selecting a mode of stereo operation.

18. The system of claim 14, wherein the means for determining comprises:

means for emitting a tone with the videoconferencing system;

means for receiving the tone with the microphones; and

means for comparing the tones received by the microphones.

19. The system of claim 14, wherein the means for determining comprises:

means for obtaining a first magnetic orientation of the videoconferencing system;

means for obtaining a second magnetic orientation of the microphones; and

means for comparing the first and second magnetic orientations.

20. The system of claim 14, wherein the means for determining comprises:

means for emitting a plurality of light signals indicative of the orientation of the microphones; and

means for detecting at least one of the light signals.

21. A method of operating a plurality of microphones for a videoconferencing system, the microphones being positionable relative to the videoconferencing system, the method comprising:

determining an orientation of the microphones relative to the videoconferencing system;

selecting a mode of stereo operation depending on the orientation of the microphones relative to the videoconferencing system; and

operating the microphones according to the selected mode of stereo operation.

22. The method of claim 21, wherein the act of selecting the mode of stereo operation comprises manually selecting the mode of stereo operation from a menu or button indicating the orientation of the microphones.

23. The method of claim 21, wherein the act of determining the orientation of the microphones comprises:

emitting a tone with the videoconferencing system;

receiving the tone with the microphones; and

comparing the tones received by the microphones to detect the orientation of the microphones.

24. The method of claim 21, wherein the act of determining the orientation of the microphones comprises:

obtaining a first magnetic orientation of the videoconferencing system;

obtaining a second magnetic orientation of the microphones; and

comparing the first and second magnetic orientations to detect the orientation of the microphones.

25. The method of claim 21, wherein the act of determining the orientation of the microphone bar comprises:

emitting a plurality of light signals indicative of the orientation of the microphones; and

detecting at least one of the light signals to detect the orientation of the microphones.